Irrigation systems are frequently used to deposit water, fertilizers, pesticides, and/or other fluids throughout a field of crops. Most irrigation systems are either center pivot or lateral (or linear) move type. Center pivot irrigation systems move in a circle or semi-circle about a central pivot while lateral irrigation systems move along a generally straight line across a square or rectangular-shaped field.
As shown in prior art FIGS. 1 and 2, a typical lateral irrigation system A includes a number of mobile towers B, interconnecting support sections C, and fluid-carrying conduits and sprinklers supported below the support sections for delivering fluids to areas beneath the irrigation system. The mobile towers are driven by motors to move the irrigation system back and forth across a field. A safety circuit with one or more switches or other devices shuts-down the motors when the mobile towers reach end-of-run barricades D or other objects that mark field boundaries or particular areas within a field. Typically, the safety switches are mounted to at least the leftmost and rightmost mobile towers to engage, sense, or otherwise interact with left and right end-of-run barricades, respectively. When either switch is triggered, the motors of all the mobile towers are stopped so that no portion of the irrigation system travels beyond a field boundary or other designated area.
Unfortunately, these safety switches can cause large areas of a field to remain unirrigated if one end of the irrigation system reaches the end of a field before the opposite end does. This may occur, as shown in prior art FIG. 1, if the motors on one side of the irrigation system move their respective mobile towers at a faster rate than the motors on the opposite side of the irrigation system. This may also occur, as shown in prior art FIG. 2, when a field boundary is not perpendicular to the lateral path of an irrigations system. In both cases, the safety circuit stops all movement of the irrigation system when any of the safety switches are activated, often leaving a generally wedge-shaped portion of the field with no irrigation. The unirrigated area can be quite large, especially for long irrigation systems. For example, a 1,250 foot long irrigation system with one end that stops 150 feet before a field boundary leaves an unirrigated area of over 2 acres.
Accordingly, there is a need for a lateral irrigation system that overcomes the limitations of the prior art.